So I have an old Creative Sound Blaster Audigy 2 laying around and I'm currently using my onboard Realtek ALC889. Now people in general seem to think that a dedicated sound card is always better than onboard sound, but the Audigy 2 is much older than the onboard sound. Which one of these would give the best sound?

My speakers are the Corsair SP2500, in other words rather decent (I guess?).